A target location may be accessed from a remote location by passing a catheter system through one or more body lumens to the target location. When the vascular system of the patient is used, the catheter system is inserted into an artery or vein percutaneously or through a small incision in the patient's body to allow the catheter system to be threaded through the patient's body to the target location. When inserting the catheter system percutaneously, an introducer sheath may be used. The introducer sheath creates a pathway or conduit to insert a variety of medical devices into the patient's vasculature and access the target location. For example, the medical devices may include surgical instruments, fiber optic cables, lasers, electronic devices, or sensors capable of monitoring one or more physiological conditions or parameters in the patient's body. Precise delivery of such medical devices may remain a challenge due to the structure at or near the target location, such as in a body cavity or due to the particular demands of the medical device delivered.
Because some medical devices are to be delivered to body cavities, a device advanced into a cavity will protrude into the cavity at approximately the angle in which the device entered the cavity. The catheter system may need to be directed toward the target location within the cavity, if the target location is not in an approximate line with the entry point of the cavity. Additionally, some procedures may require a particular alignment of the medical device beyond a particular placement. The medical device may be steered into position within the cavity after advancing the medical device through the catheter or other delivery system, but for procedures involving the use of multiple medical devices, it may further reduce time and cost of the procedure to steer and align the catheter or other delivery system to provide a consistent delivery of subsequent devices.
For example, to gain access to the left atrium of the heart, the catheter and/or access sheath may be tracked from a puncture in the femoral vein, through the inferior vena cava, into the right atrium and through a puncture in the intra-atrial septum to the left atrium. The pathway can then be used to access the mitral valve, which lies between the left atrium and the left ventricle. Since the mitral valve is located below the point of entry to into the left atrium, devices which are inserted need to be directed downward (i.e., toward the left ventricle) after entry and toward the mitral valve. Additionally, the device used for applying interventional therapies to the mitral valve may necessitate precise alignment with the valve commissures, leaflets, or coaptation line to perform the intended procedure.
The devices can also be directed through the valve chordae or papillary muscles, for example, for interventional therapy to the mitral valve. When such procedures require the use of more than one instrument, each instrument would be dependent upon proper positioning in relation to the valve. Therefore, positioning or steering mechanisms need to be built into each instrument. This adds further cost, complexity, and time to the procedures.
Other procedures may include tracking a catheter and/or access sheath from a puncture in the femoral vein through the intra-atrial septum to the left atrium. This pathway may be used to access the left atrium for ablation of the atrium wall or ablation around the pulmonary veins. Such interventional therapies would require precise alignment with target areas for proper ablation placement. Additionally, alternative access routes and/or access routes to other cavities may be desired.
To overcome some of these challenges, steerable catheter systems include one or more wires that allow manual flexion of the catheter system by an operator at a proximal end of the catheter system. The catheter system may thereby have a distal portion or other portion with an operator-adjustable curvature to allow navigation of the catheter system to the target location. A wire or wires in the catheter system, however, may shift in position within the catheter system. Further, torqueing the catheter system during navigation of the vasculature may cause changes in the position of contents in such catheter systems. Movements of the wires within the guide catheter or delivery catheter may compromise the precision with which the catheter may be oriented in the patient's body or the precision with which the operation and/or deployment of a medical device attached to the distal end thereof may be controlled.